This application claims the benefit of the Korean Application No. P2001-55685 filed on Sep. 11, 2001, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a flat cathode ray tube (CRT), and more particularly, to a flat CRT panel, which can reduce weight and breakage during heat treatment.
2. Background of the Related Art
Referring to FIG. 1, a structure of a related art color CRT will be explained.
There is a funnel 2 fitted to rear of a panel 1. There is a fluorescent film coated on an inside surface of the panel 1, and there is an electron gun 8 sealed inside of the funnel 2 for emitting an electron beam 11 that makes the fluorescent film on the panel 1 luminescent. There are a deflection yoke 9 and a magnet 10 for deflecting the electron beam 11 to a required path. There are stud pins 6 for fastening a main frame 5, to which springs 4 of a shadow mask 3 and an inner shield 7 are fitted.
The operation of the related art color CRT will be explained.
Upon application of a voltage to the electron gun 8, the electron gun 8 emits the electron beam 11. The electron beam 11 emitted thus is deflected in left or right, or up or down direction by the deflection yoke 9, and hits the fluorescent film on inside of the panel 1, according to which a picture is reproduced.
In the meantime, since an inside of the CRT is under substantially high vacuum, such that the panel 1 and the funnel 2 are under a high tension or compression, to be susceptible to implosion caused by an external impact. Consequently, in order to prevent the implosion, the panel 1 is designed to have a certain structural strength, and furthermore, there is a reinforcing band 12 strapped around an outer circumference of skirt of the panel 1, for distribution of stresses on the CRT to secure an impact resistance capability.
In the meantime, referring to FIG. 2A, most of the related art panels are not flat. That is, both an inside surface and an outside surface of the panel have certain curvatures. However, it is current trend that the CRT becomes larger and flat. That is, referring to FIG. 2B, currently a flat panel 1 having almost no curvature on the outside surface is used mostly.
Though the flat panel 1 has various advantages over the non-flat panel 1a, the flat panel 1 has a disadvantage in view of strength. Problems of the related art flat CRT will be explained.
First, referring to FIG. 3, the flat panel 1 has a distance from a mold match line to a seal edge line OMH greater than a non-flat panel 1a. That is, the flat panel 1 has an overall thickness greater than the non-flat panel 1, to cause breakage due to a high stress over a critical stress coming from a difference of heat conduction during heat treatment of the panel. That is, basically, the flat panel 1 is a structure having a limitation from breakage.
Second, the flat panel 1 is comparatively thick, and heavy, to cost high and require components, such as frame and the like, to be large sized.
Accordingly, the present invention is directed to a flat CRT panel that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a flat CRT panel which can reduce panel breakage during heat treatment (Stabi, Sealing, evacuation).
Another object of the present invention is to provide a flat CRT panel which can reduce a panel weight and cost.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the flat CRT panel includes a substantially flat outside surface, and an inside surface with a certain radius of curvature, wherein the panel is formed such that (Ts/Tm)*CFT*Rz falls on a range of 28-36, where CFT denotes a center thickness, Ts denotes a diagonal effective screen edge thickness Ts, Tm denotes a maximum thickness at an interface of the skirt and the effective screen, and Rz denotes an inside radius of curvature, i.e., a value obtained by dividing a diagonal effective screen sectional radius of curvature Rd by a representative value {Rd/(1.767*a diagonal length of the effective screen)}.
Preferably, the panel is formed such that the (Ts/Tm)*CFT*Rz falls on a range of 29-34.
Preferably, the Rd denotes a sectional radius of curvature on a diagonal axis, the Ts denotes an effective screen edge thickness on the diagonal axis of the panel, and Tm denotes a maximum thickness at an interface of a panel skirt and the effective screen.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.